SEATTLE- Boeing calls it the SPUD test. It stands for “Synthetic Personnel Using Dielectric Substitution" - a fancy way of saying, we used potatoes to stand in for people in radio testing.
Last summer, inside a retired DC-10 parked in the Arizona desert, Boeing engineers loaded sacks of potatoes in the shape of people sitting in 150 seats.
“One of our team members proposed the use of potatoes, due to the fact that potatoes have a very similar dielectric constant to humans,” said Dennis Lewis, a Boeing associate technical fellow in the area of microwave and antenna metrology for the company’s Test and Evaluation organization.
Lewis measures and calibrates electric equipment very precisely. And pound for pound, he says the potatoes affect radio waves like people do. For a long running experiment, actual people weren’t going to sit still for that long.
“It wasn’t feasible to have 200 or 300 people sit still for two or three weeks of testing,” said Lewis.
The engineers had to figure out two things: how to make internal Wi-Fi signals that people use for cell phones and laptops aboard planes ( above 10,000 feet, while in “airplane mode”) more reliable.
Right now, they’re finding gaps in the Wi-Fi signal that are affected by the people in the plane and where they sit. That makes the signal spotty. Engineers also want to know how to make sure the Wi-Fi signals don’t interfere with navigation and other safety critical parts of the airliner.